The following guide shows how to setup ROS Melodic and other important tools specific to ROS.

Setup ROS Melodic

The ROS distribution Melodic is supported by Ubuntu 18.04 which is why we are going to install it. Instructions can be found on the offical ROS documentation. Just follow these instructions and choose this configuration: Desktop-Full Install: (Recommended). Although it is overkill, it will provide all examples that you might want to try.

ROS Installation

The robot setup is supposed to run on Ubuntu 18.04 Bionic. ROS Melodic is intended to run with this Ubuntu version.

Build Tool: catkin_tools

To work with ROS we will use catkin_tools instead of catkin_make. catkin_tools provide commands such as catkin build which we will use instead of catkin_make because the catkin_tools are more actively developed than catkin_make ref.

Follow the instructions to insall catkin_tools from a Ubuntu package repository. After sucessfully installing catkin_tools we can create and initialize a workspace (called ros for this project) with the commands listed in the build_tools documentation:

Note that we already sourced the setup.bash while following the ROS installation instructions.

fjp@ubuntu:~/git/2wd-robot/ros$ mkdir -p ~/git/2wd-robot/ros/src    # Make a new workspace and source space
fjp@ubuntu:~/git/2wd-robot/ros$ cd ~/git/2wd-robot/ros              # Navigate to the workspace root
fjp@ubuntu:~/git/2wd-robot/ros$ catkin init                         # Initialize it with a hidden marker file
Initializing catkin workspace in `/home/fjp/git/2wd-robot/ros`.
----------------------------------------------------------------
Profile:                     default
Extending:             [env] /opt/ros/melodic
Workspace:                   /home/fjp/git/2wd-robot/ros
----------------------------------------------------------------
Build Space:       [missing] /home/fjp/git/2wd-robot/ros/build
Devel Space:       [missing] /home/fjp/git/2wd-robot/ros/devel
Install Space:      [unused] /home/fjp/git/2wd-robot/ros/install
Log Space:         [missing] /home/fjp/git/2wd-robot/ros/logs
Source Space:       [exists] /home/fjp/git/2wd-robot/ros/src
DESTDIR:            [unused] None
----------------------------------------------------------------
Devel Space Layout:          linked
Install Space Layout:        None
----------------------------------------------------------------
Additional CMake Args:       None
Additional Make Args:        None
Additional catkin Make Args: None
Internal Make Job Server:    True
Cache Job Environments:      False
----------------------------------------------------------------
Whitelisted Packages:        None
Blacklisted Packages:        None
----------------------------------------------------------------
Workspace configuration appears valid.
----------------------------------------------------------------

Command Overview of catkin_tools

To create packages, which will be covered in the next posts in more depth, we will use catkin create pkg PKG_NAME.

Building the workspace is done with catkin build.

fjp@ubuntu:~/git/2wd-robot/ros$ catkin build
----------------------------------------------------------------
Profile:                     default
Extending:             [env] /opt/ros/melodic
Workspace:                   /home/fjp/git/2wd-robot/ros
----------------------------------------------------------------
Build Space:        [exists] /home/fjp/git/2wd-robot/ros/build
Devel Space:        [exists] /home/fjp/git/2wd-robot/ros/devel
Install Space:      [unused] /home/fjp/git/2wd-robot/ros/install
Log Space:         [missing] /home/fjp/git/2wd-robot/ros/logs
Source Space:       [exists] /home/fjp/git/2wd-robot/ros/src
DESTDIR:            [unused] None
----------------------------------------------------------------
Devel Space Layout:          linked
Install Space Layout:        None
----------------------------------------------------------------
Additional CMake Args:       None
Additional Make Args:        None
Additional catkin Make Args: None
Internal Make Job Server:    True
Cache Job Environments:      False
----------------------------------------------------------------
Whitelisted Packages:        None
Blacklisted Packages:        None
----------------------------------------------------------------
Workspace configuration appears valid.

NOTE: Forcing CMake to run for each package.
----------------------------------------------------------------
[build] No packages were found in the source space '/home/fjp/git/2wd-robot/ros/src'
[build] No packages to be built.
[build] Package table is up to date.
Starting  >>> catkin_tools_prebuild
Finished  <<< catkin_tools_prebuild                [ 10.0 seconds ]
[build] Summary: All 1 packages succeeded!
[build]   Ignored:   None.
[build]   Warnings:  None.
[build]   Abandoned: None.
[build]   Failed:    None.
[build] Runtime: 10.1 seconds total.

Finally the newly built packages have to be loaded in the environment using source.

fjp@ubuntu:~/git/2wd-robot/ros$ source ~/git/2wd-robot/ros/devel/setup.bash # Load the workspace's environment

Resources

Although the catkin tutorial uses catkin_make it provides a helpful guide to create a workspace

ROS Style Guide

The project follows ROS conventions and the style guide from ROS in writing Python code.

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